The present invention relates to a thermostatic coolant circulating device for circulating a thermostatic coolant to a load.
FIG. 3 shows an example of a previously proposed thermostatic coolant circulating device. This circulating device 1 includes a supply circuit 3 for circulating a thermostatic coolant to a load 2 and a cooling circuit 4 for cooling the aforesaid coolant, the coolant having a temperature previously raised by cooling the load 2.
In the aforesaid supplying circuit 3, the coolant having a temperature raised by cooling the load 2 refluxes through a return pipe 6 to a heat exchanger 7. After the coolant is cooled below a set temperature in this heat exchanger 7 by heat exchange with a refrigerant flowing through an evaporator 18 of the aforesaid cooling circuit 4, the coolant flows into a heating vessel 8 and is heated by a heater 9 approximately to a set temperature. Thereafter, the coolant overflows the heating vessel 8 to flow into a tank 10. Then, the coolant is supplied to the aforesaid load 2 again through an external pipe 12 by a pump 11. In FIG. 3, a temperature sensor 13 that measures the temperature of the coolant and a temperature controller 14 that controls the aforesaid heater 9 on the basis of a measurement signal from the temperature sensor 13 are shown.
On the other hand, the aforesaid cooling circuit 4 is constructed as a sequential series connection of a compressor 15 that compresses a refrigerant into a high-temperature high-pressure refrigerant gas, a water-cooled condenser 16 that cools and condenses the refrigerant gas into a high-pressure liquid refrigerant, a pressure reducing valve 17 that reduces the pressure of the liquid refrigerant to lower the temperature thereof, the aforesaid evaporator 18 that evaporates the liquid refrigerant having the pressure reduced by the pressure reducing valve 17 by heat exchange with the coolant, and an accumulator 19.
Generally, in such a circulating device, when the operation of the aforesaid pump 11 begins and the coolant or in the tank 10 starts to be supplied to the load 2 through the external pipe 12, the amount of liquid in the tank 10 decreases by the amount that has flowed into the external pipe 12 and the load 2, thereby to lower the liquid level. For this reason, it is necessary to fill the aforesaid tank 10 with a sufficient amount of the coolant in advance so as not to cause an obstacle to the operation of the pump 11 even if the liquid level lowers. This necessarily leads to an increased amount of use of the coolant.
However, since an extremely expensive completely fluorinated liquid is used as the aforesaid coolant, the initial cost is high if the amount used is large. Therefore, it is desired to make it possible to cool the load with as small an amount of coolant as possible.
However, if the amount of the coolant to be stored in the tank is simply reduced, there is a fear that the liquid level in the tank lowers to the position of the suction inlet of the pump when the operation of the device begins and the coolant starts to be supplied to the load. This causes an obstacle to the operation of the aforesaid pump.
An object of the present invention is to provide a thermostatic coolant circulating device having a rationally designed structure with a low initial cost and being capable of cooling a load with the use of a small amount of coolant while adjusting the liquid level in a tank so as not to cause an obstacle to the operation of a pump.
In order to achieve the aforesaid object, the present invention provides a thermostatic coolant circulating device comprising a supplying circuit for circularly supplying a coolant to a load and a cooling circuit for cooling the coolant having a temperature raised by cooling the load.
The aforesaid supplying circuit comprises a tank for storing the coolant; a pump for circulating the coolant in said tank to the load through an external pipe; a coolant adjustment chamber of a closed structure having a communication aperture at a lower end thereof, the communication aperture being in communication with an inner bottom of the tank; and a gas supplying and discharging means connected to the adjustment chamber and having a function of allowing the coolant in the adjustment chamber to flow out through the communication aperture into the tank by supplying a gas into the adjustment chamber and a function of allowing a part of the coolant in the tank to flow into the adjustment chamber through the communication aperture by discharging the gas in said adjustment chamber.
In a circulating device having the aforesaid construction, when the operation thereof is stopped and the whole amount of the coolant is recollected in the tank, the gas in the adjustment chamber is discharged and a part of the coolant flows into the adjustment chamber.
When the operation of the device is started in this state, the coolant in the tank is circularly supplied to the load through the external pipe by the pump. This reduces the amount of the in the tank by the amount supplied to the load, thereby to lower the liquid level. However, in this state, the gas is supplied from the gas supplying and discharging means into the adjustment chamber and the coolant in the aforesaid adjustment chamber is discharged into the tank through the aperture, thereby compensating for the decrease in the amount of the coolant in the tank with the use of the coolant discharged from the adjustment chamber to prevent the liquid level from lowering.
In the case of stopping the operation of the aforesaid circulating device and recollecting the coolant that has flowed into the external pipe and the load to store it in the tank, the gas in the aforesaid adjustment chamber is discharged by the gas supplying and discharging means and a part of the coolant in the tank is allowed to flow into the adjustment chamber, thereby to absorb the recollected coolant from the external pipe and the load by means of the adjustment chamber.
Thus, by allowing the change of the liquid amount in the tank to be absorbed with the use of the aforesaid adjustment chamber, the load can be cooled even with a small amount of the coolant while maintaining the liquid level in the aforesaid tank so as not to cause an obstacle to the operation of the pump. Further, at the time of shutdown of the device, the can be stored with certainty by auxiliarily using the aforesaid adjustment chamber even if the volume of the tank itself is so small that the tank cannot store the whole amount of the coolant.
In the present invention, the aforesaid adjustment chamber preferably has a volume large enough to store the coolant in the aforesaid external pipe including the load.
In the present invention, the aforesaid adjustment chamber may be disposed either in the inside or on the outside of the tank.
According to one specific embodiment of the present invention, the aforesaid gas supplying and discharging means includes a compressed gas source for supplying a dried compressed gas and a switching valve connected in a pipe passageway that connects the aforesaid compressed gas source and the aforesaid adjustment chamber.
According to another specific embodiment of the present invention, the aforesaid supplying circuit includes a heat exchanger that cools the coolant having a temperature raised by cooling the load and refluxing into the tank by heat exchange with a refrigerant in the aforesaid cooling circuit, and a heater for heating the coolant cooled below a set temperature by the aforesaid heat exchanger to approximate the coolant to the set temperature.